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From: Andy Lutomirski <luto@kernel.org>
Date: Fri, 31 Mar 2017 19:18:18 -0700
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Subject: Re: [v6 PATCH 00/21] x86: Enable User-Mode Instruction Prevention
To: Stas Sergeev <stsp@list.ru>
Cc: Alexandre Julliard <julliard@winehq.org>,
        Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
        Ingo Molnar <mingo@redhat.com>, Thomas Gleixner <tglx@linutronix.de>,
        "H. Peter Anvin" <hpa@zytor.com>, Andy Lutomirski <luto@kernel.org>,
        Borislav Petkov <bp@suse.de>, Peter Zijlstra <peterz@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
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        Jiri Slaby <jslaby@suse.cz>, Jonathan Corbet <corbet@lwn.net>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Paul Gortmaker <paul.gortmaker@windriver.com>,
        Vlastimil Babka <vbabka@suse.cz>, Chen Yucong <slaoub@gmail.com>,
        Fenghua Yu <fenghua.yu@intel.com>,
        "Ravi V. Shankar" <ravi.v.shankar@intel.com>,
        Shuah Khan <shuah@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        X86 ML <x86@kernel.org>, linux-msdos@vger.kernel.org,
        wine-devel@winehq.org
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On Fri, Mar 31, 2017 at 2:26 PM, Stas Sergeev <stsp@list.ru> wrote:
> 31.03.2017 17:11, Alexandre Julliard пишет:
>>
>> In fact it would be nice to be able to make sidt/sgdt/etc. segfault
>> too. I know a new syscall is a pain,
>
> Maybe arch_prctl() then?

I still like my idea of a generic mechanism to turn off
backwards-compatibility things.  After all, hardened programs should
turn off UMIP fixups entirely.  They should also turn off vsyscall
emulation entirely, and I see no reason that these mechanisms should
be different.

--Andy